Backpacks for carrying items such as books, clothing, and other personal items are well known. Backpacks typically comprise a large central compartment into which the items are placed. Additional compartments and pockets may also be provided to separate items within the backpack. The backpack is typically outfitted with a pair of shoulder straps, and may also have a hip strap, opposed ends of which are attached to the backpack, and are used by the wearer to carry the backpack.
Such backpacks may be frameless and rely solely on the shoulder straps, hip strap and bag to support the contents of the pack. Other backpacks may include an internal or external frame. It is preferable for the weight of a pack to be carried by the hips or by the sacrum. However, frameless backpacks do not allow the weight of the backpack to be effectively transferred to the user's hips, and provide little protection for the contents of the backpack. Along with the heavier loads being carried more frequently by frameless packs comes the increased potential for fatigue, discomfort, poor posture, and even musculoskeletal disorder and injury. This places a premium on backpack design to minimize such potential. However, the suspension systems in many such backpacks are simply incapable of providing an ergonomically correct fit. A backpack with standard shoulder straps primarily carries the load on the shoulders. However, the more a load can ride on the hips, the less load pressure there is on the shoulders. Further, the closer the load is to the back of the user, the more upright the user is able to walk, and, consequently, there is less pressure on the hip joints.
Known backpacks with internal or external frames allow the weight of the backpack to be carried by the user's hips, but typically do not provide much protection for the contents of the backpack. Some backpacks are formed of a dimensionally stable material, e.g., plastic. However, such backpacks can present problems to the user, since it can be uncomfortable to have a hard plastic backpack directly against one's back.
Other known backpacks are limiting in that their shells do not provide any resiliency or torsional flexibility. Rigid backpacks cannot be compressed at all, and, therefore the contents of the backpack may get tossed and turned as the user moves. Further, a rigid backpack provides no absorption of shocks when the backpack is set down by the user, potentially leading to disruption and/or damage of its contents.
It is an object of the present invention to provide a backpack with an external frame that reduces or overcomes some or all of the difficulties inherent in prior known devices. Particular objects and advantages of the invention will be apparent to those skilled in the art, that is, those who are knowledgeable or experienced in this field of technology, in view of the following disclosure of the invention and detailed description of certain preferred embodiments.